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-rw-r--r--llvm/lib/Transforms/Utils/BasicBlockUtils.cpp7
-rw-r--r--llvm/lib/Transforms/Utils/LoopUnroll.cpp64
-rw-r--r--llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp4
3 files changed, 13 insertions, 62 deletions
diff --git a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
index aa7b933022c..842434cca15 100644
--- a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -38,6 +38,8 @@
#include "llvm/IR/Value.h"
#include "llvm/IR/ValueHandle.h"
#include "llvm/Support/Casting.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/Local.h"
#include <cassert>
#include <cstdint>
@@ -47,6 +49,8 @@
using namespace llvm;
+#define DEBUG_TYPE "basicblock-utils"
+
void llvm::DetatchDeadBlocks(
ArrayRef<BasicBlock *> BBs,
SmallVectorImpl<DominatorTree::UpdateType> *Updates,
@@ -190,6 +194,9 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, DomTreeUpdater *DTU,
if (IncValue == &PN)
return false;
+ LLVM_DEBUG(dbgs() << "Merging: " << BB->getName() << " into "
+ << PredBB->getName() << "\n");
+
// Begin by getting rid of unneeded PHIs.
SmallVector<AssertingVH<Value>, 4> IncomingValues;
if (isa<PHINode>(BB->front())) {
diff --git a/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
index d8ac42b5a85..d0908b594c9 100644
--- a/llvm/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
@@ -93,66 +93,6 @@ void llvm::remapInstruction(Instruction *I, ValueToValueMapTy &VMap) {
}
}
-/// Folds a basic block into its predecessor if it only has one predecessor, and
-/// that predecessor only has one successor.
-/// The LoopInfo Analysis that is passed will be kept consistent.
-BasicBlock *llvm::foldBlockIntoPredecessor(BasicBlock *BB, LoopInfo *LI,
- ScalarEvolution *SE,
- DominatorTree *DT) {
- // Merge basic blocks into their predecessor if there is only one distinct
- // pred, and if there is only one distinct successor of the predecessor, and
- // if there are no PHI nodes.
- BasicBlock *OnlyPred = BB->getSinglePredecessor();
- if (!OnlyPred) return nullptr;
-
- if (OnlyPred->getTerminator()->getNumSuccessors() != 1)
- return nullptr;
-
- LLVM_DEBUG(dbgs() << "Merging: " << BB->getName() << " into "
- << OnlyPred->getName() << "\n");
-
- // Resolve any PHI nodes at the start of the block. They are all
- // guaranteed to have exactly one entry if they exist, unless there are
- // multiple duplicate (but guaranteed to be equal) entries for the
- // incoming edges. This occurs when there are multiple edges from
- // OnlyPred to OnlySucc.
- FoldSingleEntryPHINodes(BB);
-
- // Delete the unconditional branch from the predecessor...
- OnlyPred->getInstList().pop_back();
-
- // Make all PHI nodes that referred to BB now refer to Pred as their
- // source...
- BB->replaceAllUsesWith(OnlyPred);
-
- // Move all definitions in the successor to the predecessor...
- OnlyPred->getInstList().splice(OnlyPred->end(), BB->getInstList());
-
- // OldName will be valid until erased.
- StringRef OldName = BB->getName();
-
- // Erase the old block and update dominator info.
- if (DT)
- if (DomTreeNode *DTN = DT->getNode(BB)) {
- DomTreeNode *PredDTN = DT->getNode(OnlyPred);
- SmallVector<DomTreeNode *, 8> Children(DTN->begin(), DTN->end());
- for (auto *DI : Children)
- DT->changeImmediateDominator(DI, PredDTN);
-
- DT->eraseNode(BB);
- }
-
- LI->removeBlock(BB);
-
- // Inherit predecessor's name if it exists...
- if (!OldName.empty() && !OnlyPred->hasName())
- OnlyPred->setName(OldName);
-
- BB->eraseFromParent();
-
- return OnlyPred;
-}
-
/// Check if unrolling created a situation where we need to insert phi nodes to
/// preserve LCSSA form.
/// \param Blocks is a vector of basic blocks representing unrolled loop.
@@ -818,12 +758,14 @@ LoopUnrollResult llvm::UnrollLoop(Loop *L, UnrollLoopOptions ULO, LoopInfo *LI,
assert(!DT || !UnrollVerifyDomtree ||
DT->verify(DominatorTree::VerificationLevel::Fast));
+ DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Eager);
// Merge adjacent basic blocks, if possible.
for (BasicBlock *Latch : Latches) {
BranchInst *Term = cast<BranchInst>(Latch->getTerminator());
if (Term->isUnconditional()) {
BasicBlock *Dest = Term->getSuccessor(0);
- if (BasicBlock *Fold = foldBlockIntoPredecessor(Dest, LI, SE, DT)) {
+ BasicBlock *Fold = Dest->getUniquePredecessor();
+ if (MergeBlockIntoPredecessor(Dest, &DTU, LI)) {
// Dest has been folded into Fold. Update our worklists accordingly.
std::replace(Latches.begin(), Latches.end(), Dest, Fold);
UnrolledLoopBlocks.erase(std::remove(UnrolledLoopBlocks.begin(),
diff --git a/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp b/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
index a53ee9d2687..ff49d83f25c 100644
--- a/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
@@ -538,12 +538,14 @@ LoopUnrollResult llvm::UnrollAndJamLoop(
MergeBlocks.insert(ForeBlocksLast.begin(), ForeBlocksLast.end());
MergeBlocks.insert(SubLoopBlocksLast.begin(), SubLoopBlocksLast.end());
MergeBlocks.insert(AftBlocksLast.begin(), AftBlocksLast.end());
+ DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Eager);
while (!MergeBlocks.empty()) {
BasicBlock *BB = *MergeBlocks.begin();
BranchInst *Term = dyn_cast<BranchInst>(BB->getTerminator());
if (Term && Term->isUnconditional() && L->contains(Term->getSuccessor(0))) {
BasicBlock *Dest = Term->getSuccessor(0);
- if (BasicBlock *Fold = foldBlockIntoPredecessor(Dest, LI, SE, DT)) {
+ BasicBlock *Fold = Dest->getUniquePredecessor();
+ if (MergeBlockIntoPredecessor(Dest, &DTU, LI)) {
// Don't remove BB and add Fold as they are the same BB
assert(Fold == BB);
(void)Fold;
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